caustic - Sarcastic or severely critical, often in a hurtful or biting manner; or able to burn or corrode organic tissue, typically referring to chemicals or substances.
The caustic chemical spilled onto the floor and quickly started to eat away at the floor surface.
hillbilly - A person from a rural, mountainous area of the United States, especially the Appalachians. Can be used in an insulting manner.
The hillbilly family made a store in Alabama, and its theme is that the families in rural America may not be sophisticated, but they have a big heart and close family ties.